As a typical engineering plastic, polyarylene sulfide has recently been in considerable demand as a material for high temperature and corrosive environments and electronic products due to its excellence in thermal resistance, chemical resistance, flame resistance, and electrical insulation properties. Polyarylene sulfide is primarily used for computer parts, automotive components, protective coatings against corrosive chemicals, industrial chemical resistant fabrics, and so forth.
The only polyarylene sulfide that is commercially available is polyphenylene sulfide (hereinafter referred to as PPS). The current industrial synthesis process for PPS involves a reaction of p-dichlorobenzene (hereinafter referred to as pDCB) and sodium sulfide in a polar organic solvent such as N-methylpyrrolidone. This process is known as the Macallum process, which is based on U.S. Pat. Nos. 2,513,188 and 2,583,941. Although some other types of usable polar solvents have been proposed in the PPS commercial production process, the mostly used one is N-methylpyrrolidone. The PPS production process is generally conducted using dichloro aromatic compounds as a reactant and yields sodium chloride as a byproduct.
Meanwhile, PPS obtained in the Macallum process generally has high flowability, and thus is able to mold a product even at a low pressure. Therefore, it has been known to have high processability. However, when PPS is used to form products requiring high precision or having a flat shape, such as a variety of computer parts or electronic products, burrs (flashes) are generated on the molded products, and thus there is a limit in its application to the production of precision parts.